Garrison, IA 52229 Frost Dates
52229, near Garrison, IA: the frost window
Typically, the last spring freeze lands around 04/28, roughly 243 days out. Fall's first freeze usually shows up around 10/10, roughly 165 days after the last spring frost.
Garrison sits in USDA Zone 5a (-20 to -15°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Garrison's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Garrison's last frost
04/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/14 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/11 and only about 1 year in 10 sees frost after that.
Garrison against the rest of the dataset
Garrison's growing season runs about 165 days, ranking 30,726 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 543 of 1,042.
Learn more
Two guides worth reading on 52229: zone vs. frost date, on why Zone 5a and Garrison's frost date answer different questions, and the frost range, on how to read the range around Garrison's dates instead of trusting one.